scholarly journals The influence of fencing on seedling establishment during reforestation of oak stands: a comparison of artificial and natural regeneration techniques including costs

Author(s):  
Magnus Löf ◽  
Julien Barrere ◽  
Mattias Engman ◽  
Linda K. Petersson ◽  
Adrian Villalobos

AbstractIn temperate Europe, oak-dominated forests are widespread, supporting high biodiversity and providing important ecosystem services. Insufficient natural regeneration has, however, been a concern for over a century. The objective of this study was to gain insights into differences in regeneration success using artificial and natural regeneration techniques for reforestation of oak (Quercus robur L.) stands. We monitored seedlings following planting, direct seeding and natural regeneration over five years in a randomized block experiment in southern Sweden with fenced and non-fenced plots. Fencing had a strong positive effect on height growth, especially for planted seedlings that were taller than the other seedlings and more frequently browsed in non-fenced plots. In contrast, there was little effect of fencing on survival, establishment rate and recruitment rate of seedlings. Due to aboveground damage on seedlings from voles, protection of acorns did not improve establishment rate following direct seeding. Under current circumstances at the site with a sparse shelterwood of old oaks, we conclude that natural regeneration was the most cost-efficient regeneration method. It resulted in the most seedlings at the lowest cost. However, regeneration success was heavily influenced by interference from herbaceous vegetation. With a small additional investment in vegetation control, the results might have been improved for planting and direct seeding.

1999 ◽  
Vol 75 (5) ◽  
pp. 821-831 ◽  
Author(s):  
Martin Béland ◽  
Yves Bergeron ◽  
Richard Zarnovican

A 36-ha experiment was carried out to assess the possibility of naturally regenerating jack pine stands following harvesting on clay soils of northwestern Quebec. Although differences between treatments were not statistically significant, there was a trend toward a positive effect of one treatment combining on-site delimbing and scarification with the Silva Wadell™ cone scarifier on jack pine seedling density (up to 10 000/ha) and distribution (50% of 1 m2 plots with at least one seedling, corresponding to 94% with 4 m2 plots), two years after harvest. However, scarified microsites contained fewer seedlings than expected and undisturbed humus contained more seedlings than expected. This result, contrary to what is generally reported in the literature may be explained either by the fairly humid conditions, favourable to germination and seedling establishment, occurring on clay sites or by the scarifier spreading the cone-bearing slash outward. Seedling abundance and distribution improved substantially from the first year to the second year following treatment. Although the irregular branch distribution over the cutover area appears to have limited regeneration success, combining on-site delimbing with soil scarification could lead to relatively good stocking of jack pine regeneration that could be enhanced by some fill-planting. This regeneration method could constitute an alternative to planting jack pine on clay. However, vegetation control to remove aspen competition might be necessary. Key words: jackpine, silviculture, natural regeneration, boreal mixed wood


Author(s):  
Д.В. Гусев

Естественное возобновление является важным фактором формирования насаждений, особенно главных лесообразующих пород. Растительное сообщество становится жизнестойким при условии способности восстановить численность популяций заменой погибших экземпляров новыми. Было выяснено в каком количестве происходит естественное возобновление сосны на гарях по сравнению с граничащими участками, не пройденными пожарами, взятые в качестве контроля. Район исследований относится к южной подзоне тайги на территории Ленинградской области в Кировском и Лужском лесничествах. Объектом исследований стали сосновые насаждения, где работы проводились в летний период с 2013 по 2015 год. Всего подобрано 36 участков (включая контроль) размером не более 0,3 га. Учет подроста проводился на учетных площадках. Каждая учетная площадка закладывалась при помощи шеста длиной 178,5 см. Площадь круговых площадок составляла 10 м2, они расположены последовательно друг за другом с непосредственным примыканием. На каждой площадке проводили перечет подроста и делили его по высоте на три категории крупности: мелкий до 0,5 м, средний – 0,6–1,5 м и крупный – более 1,5 м. А также естественное возобновление на участках делили по густоте – на три категории: редкий – до 2 тыс., средней густоты – 2–8 тыс., густой – более 8 тыс. растений на 1 га; по распределению по площади – на три категории в зависимости от встречаемости. Анализ послепожарного возобновления в сосняках показал, что на пробных площадях наблюдается отличное возобновление подроста сосны и обилие на площади, все это связано с уничтожением лесной подстилки, увеличением минерализации почвы что, в конечном счете, положительно влияет на естественное лесовосстановление, о чем свидетельствует появление всходов, а также лучше становится гидрологический режим почвы. Благодаря этому происходит хорошее восстановление. Количество благонадежного подроста составляет от 3,5 до 11,9 тыс. шт./га и его достаточно для естественного восстановления ценопопуляции после пожара. Подтверждена зависимость количество самосева и толщины лесной подстилки. Прогретая после пожара, богатая минеральными веществами почва благоприятна для появления всходов и самосева древесных растений. Natural regeneration is an important factor in the formation of plantations, especially the main forest-forming species. Plant community becomes viable, provided the ability to recover populations, replacement of lost copies new. Find out how much happens in a natural pine regeneration in burned areas compared to adjacent areas not affected by fires, are taken as a control. The study area belongs to the subzone of southern taiga on the territory of Leningrad region, the Kirov and Luga districts. The object of research became pine plantations where the work was carried out in year period from 2013 to 2015. Just picked up 36 stations (including the control) no larger than 0.3 hectares. accounting for the undergrowth was conducted on index sites. Each user platform was laid with a pole length of 178.5 cm the area of the circular pads was 10 m2, they are located successively one after another with a direct connection. At each site conducted the translation of the undergrowth and it was divided in height into three categories of size: small up to 0.5 m, average 0.6 to 1.5 meters and large – more than 1.5 meters. And natural regeneration on plots divided by the density for three categories: rare – up to 2 thousand, medium density – 2 to 8 thousand, thick – more than 8 thousand plants per 1 ha; on the distribution of the area – into three categories depending on the occurrence. Analysis of post-fire regeneration in pine forests showed that the sample areas there is a great renewal of undergrowth of pine and the abundance on the square, all this is due to the destruction of forest litter, increasing salinity of the soil which, ultimately, has a positive effect on natural regeneration, as evidenced by the appearance of seedlings, as well as better hydrological regime of the soil. Which a good recovery. The number of reliable undergrowth is from 3.5 to 11.9 thousand PCs/ha, enough for natural regeneration of seedlings after the fire. Confirmed the dependence of the number of self-seeding and thickness of forest litter. After the fire-warmed, mineral-rich soil is favorable for emergence and self-seeding of woody plants.


2019 ◽  
Vol 41 (1) ◽  
pp. 33
Author(s):  
Mounir Louhaichi ◽  
Sawsan Hassan ◽  
Ali Mekki Missaoui ◽  
Serkan Ates ◽  
Steven L. Petersen ◽  
...  

Direct seeding techniques often result in unsatisfactory outcomes in rangeland rehabilitation, primarily because of low seedling emergence and poor establishment. Seed processing techniques aimed at improving seedling emergence have gained interest by pasture managers. The purpose of this study was to investigate the combined effects of bracteole removal and seeding rate on seedling emergence in seven halophytic species: Atriplex halimus, A. canescens, A. leucoclada, A. nummularia, A. lentiformis, Salsola vermiculata and Haloxylon aphyllum under semi-arid conditions in Tel Hadya (Syria). Each of these species was evaluated for seedling emergence under two seed treatments (bracteoles removed and non-removed bracteoles) with three seeding rates (10, 30 and 60 seeds per pot), in a completely randomised block design. The results showed a positive effect of seed treatment on seedling emergence for all studied species. The native A. halimus had the highest emergence percentages whereas the introduced A. mummularia, had the lowest. However, there were no significant effects of seeding rates on seedling emergence. These results showed that bracteole removal could improve germination and seedling emergence, and potentially increase the rate of establishment of the species studied. Therefore, when implementing rangeland rehabilitation projects, bracteole removal needs to be considered. The native S. vermiculata should be recommended for direct seeding in the West Asia and North Africa region given its high seedling emergence, known high palatability, nutritive value, and high auto-regeneration performance.


1999 ◽  
Vol 29 (7) ◽  
pp. 960-967 ◽  
Author(s):  
Harold Quicke ◽  
Glenn Glover ◽  
Ralph S Meldahl

Growth of Pinus taeda L., with and without control of competing herbaceous vegetation, was evaluated over 15 years at planting densities ranging from 747 to 2990 trees/ha. A height response to vegetation control of 0.9 m at age 5 decreased to 0.3 m at age 15. Convergence in the cumulative height between treated and untreated stands did not translate into converging basal area and volume yield. For 1500 and 2200 trees/ha, volume response to early vegetation control increased to age 15. For 800 trees/ha volume gains increased to age 12 and were stable between ages 12 and 15. Higher densities apparently captured more of the site resources made available through vegetation control. Age-15 volume gains for 2200, 1500, and 800 trees/ha were 71 (23%), 48 (17%), and 19 m3·ha-1 (8%), respectively. A separate adjustment term in height and basal-area models captured the short-term positive effect of vegetation control on height growth and longer term basal-area responses. Previously published height and basal-area models were modified to account for planting-density effects.


2014 ◽  
Vol 16 (4) ◽  
pp. 732-742 ◽  

<div> <p>The natural regeneration of Scots pine stands at the Sarakatsana location in the Pieria Mountains improved considerably after the removal of the dense ground vegetation followed mechanical soil scarification. The experimental design consisted of replications on scarified and non-scarified soil. The results four years after the experiment was set up showed that regeneration reached 59 seedlings m-2 in scarified and 7 seedlings m-2 in non-scarified soil. Soil scarification seems to have had a positive effect on the emergence and survival of naturally regenerated Scots pine. The negligible number of dead seedlings in the first two measurements could be due to the favourable site and/or good climatic conditions. Although the mother stand appears to be in a critical condition due to age and increased necrosis as a result of fungal attacks, there is still considerable potential for regeneration in terms of fructification and seed production. The study findings indicate that there can be new growth of Scots pine forest with the shelterwood method of natural regeneration in combination with soil scarification.</p> </div> <p>&nbsp;</p>


2020 ◽  
Vol 29 (1) ◽  
pp. eSC03
Author(s):  
Rodrigo Balaguer-Romano ◽  
Helios Sainz-Ollero ◽  
Fernando Vasco-Encuentra

Aim of study: To evaluate demographical dynamics of yew populations in the Iberian Mediterranean mountains in order to assess population trends and a hypothetical natural regeneration of the species.Area of study: Ayllón Mountain Range, Eastern end of Central Mountain Range, Spain.Material and methods: Afield survey was conducted on three yew groves, taking data of altitude, orientation, companion woody species, UTM coordinates, height, perimeter (at breast height, 120cm) and sex. Individuals were classified in four age groups, considering height and trunk perimeter: AgeGroup1, Seedling; AgeGroup2, Juvenile; AgeGroup3, Adult and AgeGroup4, Old. Finally Recruitment rate was calculated for each population.Main results: Surveyed yew populations include more than 1600 trees, showing elevated Recruitment rates, which indicates that there are more seedling and juvenile individuals (Group1 and Group2) than adult and old ones (Group3 and Group4).Research highlights: Surveyed yew populations show vigorous regeneration. These results lead us to reconsider the relictic character assigned to the species in the Iberian Mediterranean mountains.Key words: Ayllón; microclimatic; regeneration rate; relictic; survey.


2015 ◽  
Vol 9 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Diana Borovikova ◽  
Indrikis Muiznieks ◽  
Alexander Rapoport

A new test-system was developed for rapid evaluation of the cytoprotective potential of substances which can be included in cosmetics and health care compositions. It was evaluated by changes of the viability of yeast cells after dehydration/rehydration (D/R) treatment. To check the efficiency of proposed test system we studied the effects of water extracts of the natural peloid, which are used in balneotherapy procedures. It was revealed that the resistance to D/R of cells incubated in peloid water extracts (PWE) was significantly increased (by 30-38%) already after their short incubation in the solutions with low concentrations of the PWE. Meanwhile the membrane permeability was significantly decreased after incubation with PWE. The viability of yeast cells which were more sensitive to D/R stress was increased by PWE to larger extent than the viability of the cells that were initially more resistant to this stress. The positive effect PWE upon yeast cell viability after D/R treatment can be linked with the stabilisation of the cells’ plasma membrane. The results obtained in this study indicate that this new test-system can be recommended as fast, simple and cost-efficient assay for the evaluation of various substances effects upon eukaryotic cells including also the ingredients for cosmetic products.


2012 ◽  
Vol 42 (4) ◽  
pp. 720-732 ◽  
Author(s):  
Jarosław G. Paluch ◽  
Hanna J. Stępniewska

An increased incidence of fungal pathogens has been recognized as one of the most important causes for insufficient natural regeneration in pure Abies alba Mill. forests in the Western Carpathians (central Europe). We investigated the spatial distribution of A. alba seedlings in seven stands in which severe symptoms of fungal pathogen infections were observable and compared microsite variables and ectomycorrhizal status of seedlings in locations with abundant or poor regeneration. We also tested the effect of local stand density, seedbed, and vegetation control on seed germination and the survival of 1-year seedlings. The study provided evidence that gap environment may increase the mortality of 1-year seedlings caused by fungal pathogens. That pattern was consistent with the spatial distribution of older seedlings: locations with abundant older regeneration were characterized by a greater local stand density, lower canopy openness, and lower mineral topsoil moisture than poorly regenerated locations. Yet, despite considerable spatial differentiation in ectomycorrhizal types, the mycorrhizal status of 2-year seedlings in abundantly regenerated areas did not differ from that in poorly regenerated areas.


2018 ◽  
Vol 48 (4) ◽  
pp. 371-387 ◽  
Author(s):  
R.L. Fleming ◽  
J.-D. Leblanc ◽  
T. Weldon ◽  
P.W. Hazlett ◽  
D.S. Mossa ◽  
...  

Currently, there are uncertainties regarding the impacts and (or) efficacy of biomass harvesting and silvicultural practices on stand production on coarse-textured boreal soils. Replicated factorial field experiments examining effects of complete vegetation control (repeated glyphosate application) following operational stem-only harvest with disc trenching (SOT), operational whole-tree harvest with (WTT) and without (WT) disc trenching, and whole-tree harvest with complete forest floor removal by blading (WTB) and blading followed by compaction (WTBC) were installed on four sandy northern Ontario jack pine (Pinus banksiana Lamb.) sites. Over 20 years, WTB improved planted-tree survival but decreased longer term stand productivity in comparison with other harvest intensity – soil disturbance treatments. Vegetation control improved tree growth and stand productivity initially, but over time, benefits declined substantially. SOT and WTT had similar impacts on stand production. Disc trenching improved initial planted-tree growth (WTT vs. WT), particularly without vegetation control. Jack pine natural regeneration was greatest with SOT, accounting for 25% of stand biomass at year 20. Stand structure effects included increased size inequality of naturals with WTB and reduced size inequality and asymmetry of naturals with vegetation control. Overall, impacts of forest floor removal and natural regeneration on stand development have become increasingly important over time compared with those of vegetation control.


Forests ◽  
2017 ◽  
Vol 8 (9) ◽  
pp. 353 ◽  
Author(s):  
Francisco García-Morote ◽  
Eduardo Martínez-García ◽  
Manuela Andrés-Abellán ◽  
Eva Caballero ◽  
Heli Miettinen ◽  
...  

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